Tokyo -LRB- CNN -RRB- -- Video posted to YouTube shows the dramatic moment a food stall exploded at a fireworks festival in Japan on Thursday evening .

More than 100,000 people had gathered for the annual pyrotechnic display in Fukuchiyama city , said the local chamber of commerce and industry , which organized the event .

The video shows flames leaping from the stall 's awning , then screams after a second explosion less than two minutes later .

People are seen lying on the ground receiving treatment , before firefighters race to the scene .

Sixty people were taken to a number of hospitals , suffering from varying degrees of burns , authorities said .

At one hospital alone , 16 people ages 8 to 85 years were treated for serious burns . Others were taken to more than 10 hospitals , some outside Kyoto prefecture .

Police are investigating the cause of the blaze , which local media said was believed to have started when the operator of a food stall that sells `` baby kasutera , '' a popular sponge-cake in Japan , tried to refuel his generator .

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Dozens injured when food wagon explodes at fireworks festival

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Blast happened before fireworks started at Fukuchiyama city in Kyoto

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It 's believed food vendor was trying to refuel generator when blast occurred